Coated semiconductor processing members having chlorine and fluorine plasma erosion resistance and complex oxide coatings therefor

ABSTRACT

A semiconductor processing member is provided, including a body and a plasma spray coating provided on the body. The coating is an ABO or ABCO complex oxide solid solution composition, where A, B and C are selected from the group consisting of La, Zr, Ce, Gd, Y, Yb and Si, and O is an oxide. The coating imparts both chlorine and fluorine plasma erosion resistance, reduces particle generation during plasma etching, and prevents spalling of the coating during wet cleaning of the semiconductor processing member.

FIELD OF THE INVENTION

This invention relates to semiconductor processing chambers or membersoperating with plasma assisted etching or deposition processes. Morespecifically, the invention relates to complex oxide coatings applied onvacuum and plasma chamber components to prevent particle generation, toprovide dielectric protection, to provide wet clean resistance, tomaintain a high purity environment for the creation of criticaldimensions and features of semiconductor devices produced therein and toprovide an extended life for the coated chamber components.

BACKGROUND OF THE INVENTION

Processing chambers used for making semiconductor devices involvedeposition and etching processes performed in vacuum environments. Theseprocesses also require plasma chemistries to etch or deposit conductorsand dielectric materials on various substrates (wafers). These wafersare mostly made of Si, but may also be made of GaAs or GaN. During suchplasma processes, where plasma generated chemistries are directedtowards a wafer by means of voltage biasing or electromagnetics, thewalls and components of the processing chambers that surround a waferare also exposed to those etching chemistries. The etching of materialfrom the chamber walls and various components inside the vacuum chamberresults in particle generation, which is undesirable. These particlescan land on the wafers and result in damage to the critical submicronfeatures and functionality of the semiconductor devices that that arebeing etched or deposited thereon. Currently, there is a growing need tomake these submicron critical features smaller and smaller to make evendenser semiconductor devices. These submicron features have criticaldimensions, and the future generation of semiconductors is moving towarda critical size of the order of 20 nm and beyond. Such a reduction inthe critical dimensions requires further reductions of particlegeneration inside these process chambers.

Particle generation from the chamber walls in a semiconductorchamber/member can lead to other problems, as well. The physicalpresence of eroded metallic particles in parts per million on a processwafer can also cause electrical shorting between two nearby conductors.In addition, if the generated particles diffuse into the wafer matrix,they can result in uncontrolled ion mobility, thereby causing thesemiconductor device to malfunction. The success of these nanometerdevices and the critical features thereof therefore require that thewalls of the process chambers are protected from plasma erosion. And ifwalls are eroded, it is important that very few particles are releasedon to a wafer that could possibly cause any malfunctions of the formeddevices.

One method of providing such protection from particle generationinvolves using thermal sprayed coatings that are resistant to plasmaerosion. An initial approach to chamber wall protection focused onanodization, and thermal sprayed coatings made of Al₂O₃ became amaterial of choice. U.S. Pat. No. 4,419,201 discloses the use of Al₂O₃coatings to resist erosion caused by chlorine plasma. U.S. Pat. No.5,637,237 further discloses a plasma etch chamber where the chamber wallsurfaces are coated with Al₂O₃, Y₂O₃ and Sc₂O₃ to reduce erosion ofwalls exposed to plasma. The recent introduction of aggressive, highdensity fluorine plasma results in the rapid etching of Al₂O₃ coatedchamber walls and the generation of AlF particles. The AlF particlesform dust inside the process chamber, have proven to be difficult toremove, and cause wafer-level defects in semiconductor devices.

Y₂O₃ coatings then became a material of choice, however, the use of Y₂O₃coatings has also resulted in problems. That is, while yttria coatingshave been successful in resisting fluorine plasma erosion, thesecoatings rapidly erode when exposed to chlorine plasma. Another drawbackof yttria coatings is the delamination of these coatings when exposed toaqueous cleaning processes outside the semiconductor chambers. Thepresence of yttrium fluoride and yttrium oxyfluoride particles has alsocaused problems at the wafer-level. As a result, a number ofpublications and patents have addressed the need for improvements inyttria coatings to solve these various problems.

For example U.S. Pat. No. 6,776,873 discloses combining Al₂O₃ with Y₂O₃to provide resistance to fluorine and oxygen plasma. U.S. Pat. No.7,494,723 discloses a method of densifying a top layer of a Y₂O₃ coatingwith e-beam radiation to provide increased erosion resistance. U.S.patent application publication No. 2010/0272982 A1 describes the use ofyttria stabilized zirconia coatings that provide plasma erosionresistance and wet cleaning resistance. U.S. Patent applicationpublication No. 2012/0177908 A1 discloses the use of a porosity gradientin Y₂O₃ and Zr₂O₃ coatings to gain higher thermal resistance in additionto plasma resistance. U.S. patent application publication 2012/0196139A1 describes a multilayer coating structure to gain plasma erosionresistance and wet cleaning resistance. U.S. patent applicationpublication No. 2015/0376760 A1 and International Publication No. WO2015/199752A1 disclose providing controlled emissivity coatings forchamber components to gain thermal enhancement and improved plasmaerosion resistance.

However, all of these earlier solutions are based on the use of singleoxide materials classified as AO, where A is a metal and O is the oxide;like Al₂O₃, Y₂O₃, Ce₂O₃, Gd₂O₃, HfO₂, ZrO₂, etc. As such, there is stilla need to understand the benefits provided by the use of multicomponent,complex oxides with respect to improved resistance to plasma erosion andsubsequent wet cleaning resistance to provide the next generation ofproductivity solutions for the semiconductor processing members.

The processes used in semiconductor chambers are also evolving and a newgeneration of coating materials is desired that can provide neededsolutions beyond yttria. One of the needs is to have coating materialsthat can withstand both fluorine and chlorine plasma inside the chamber,thereby preventing particle generation. It is also desired that thesematerials should have sufficient dielectric strength to withstand thevoltages present in a semiconductor process chamber. In addition to theplasma erosion resistance inside these vacuum tools, the coatings mustalso provide resistance to spallation and/or erosion when the componentsare later wet cleaned to remove materials deposited during varioussemiconductor etching or deposition processes.

To address the prevention of erosion of the semiconductor chambercomponents, the prior art has heretofore been focused on the use ofsingle oxides, and no recognition has been made with respect to the useof complex oxides, where all of the oxides are in a solid solution andhave a controlled purity of specific elements in ppm.

SUMMARY OF THE INVENTION

The present invention addresses the problem of plasma erosion resistanceand subsequent particle generation for both the fluorine and chlorinebased plasma, and also considers wet corrosion issues along with thecontrol of specific elements in parts per million (ppm). In view of theabove, the present invention provides plasma sprayed coatings forsemiconductor chamber members made of complex oxides having the solidsolution ABO and ABCO compositions, wherein A, B and C represent variousmetals and O represents oxides thereof.

According to a first aspect of the present invention, a semiconductorprocessing member is provided, comprising a body, and a plasma spraycoating provided on the body. The coating is an ABO or ABCO complexoxide solid solution composition, where A, B and C are selected from thegroup consisting of La, Zr, Ce, Gd, Y, Yb and Si, and O is an oxide,whereby the coating imparts both chlorine and fluorine plasma erosionresistance, reduces particle generation during plasma etching, andprevents spalling of the coating during wet cleaning of the member.

Preferably, the coating is selected from the group consisting ofLa₂Zr₂O₇, La_(1.5)Ce_(0.5)Zr₂O₇, Ce_(0.25)Zr_(0.75)O₂,Ce_(0.7)Gd_(0.3)O₂, Y_(0.15)Zr_(0.85)O_(1.93) and Y₂Si₂O₇. It is alsopreferred that the coating contains less than 50 ppm of any traceelement, more preferably, less than 20 ppm of any heavy metal, less than10 ppm of any alkaline metal, and less than 2 ppm of each of Fe, Ni andCu.

The body is a bare aluminum alloy body, and preferably, the body is ananodized aluminum alloy body. It is also preferred that an outermostsurface of the coating has a surface roughness in a range of 80 to 150μin Ra, wherein a peak to valley ratio, Rp/Rv, of the surface is in arange of 0.30 to 0.60.

It is also preferred that the semiconductor processing member furthercomprises a bonding layer between the coating and the body to improve atensile bond strength of the coating, and that the bond layer isselected from the group consisting of (1) Si and (2) co-phased fullystabilized zirconia and Y₂O₃.

According to the present invention, the coating reduces contamination ofa working wafer in the semiconductor tool so that an amount of Nameasured on the wafer is less than 1×10¹⁴ atoms/cm².

According to another aspect of the present invention, a plasma sprayedcoating for semiconductor processing members is provided, wherein thecoating is selected from the group consisting of solid solutions ofLa₂Zr₂O₇, La_(1.5)Ce_(0.5)Zr₂O₇, Ce_(0.25)Zr_(0.75)O₂,Ce_(0.7)Gd_(0.3)O₂, Y_(0.15)Zr_(0.85)O_(1.93) and Y₂Si₂O₇, and whereinthe coating imparts both chlorine and fluorine plasma erosionresistance, reduces particle generation during plasma etching, andprevents spalling of the coating during wet cleaning.

Preferably, the coating contains less than 50 ppm of any trace element,and more preferably, the coating contains less than 20 ppm of any heavymetal, less than 10 ppm of any alkaline metal, and less than 2 ppm ofeach of Fe, Ni and Cu. It is also preferred that an outermost surface ofthe coating has a surface roughness in a range of 80 to 150 μin Ra,where a peak to valley ratio, Rp/Rv, of the surface is in a range of0.30 to 0.60.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in detail herein below in connectionwith the associated drawing figures, in which:

FIG. 1 is a graph showing the acid solubility for the test andcomparative sample materials in HCL and H₂SO₄ measured over 24 hours asa function of weight % loss;

FIG. 2 is a graph showing the plasma erosion rate as a function ofthickness loss for the test and comparative materials (Yttria);

FIG. 3 is a schematic view of a coated cylindrical shell (body) madefrom 6061 Al alloy representing a commonly used plasma etch chambershape;

FIG. 4 is a schematic cross-sectional view of a coated chamber componentbody post-testing;

FIG. 5 is a schematic cross-sectional view of a coated component member(body) including a bonding layer; and

FIG. 6 is a graph showing the helium leak rate at 20 torr versus thelife cycle of coated electrostatic chucks.

DETAILED DESCRIPTION OF THE INVENTION

Specific materials that are resistant to fluorine and chlorinechemistries were initially examined to understand their thermodynamicresponse to the reactions that take place in a semiconductor processingchamber, such as a reactive ion etch (RIE).

Pyrochlores, fluorites and perovskites were analyzed. More specifically,materials from the general families of LaZrO, LaCeZrO, LaGdZrO, YSiO,GdZrO, GdCeO, LaCeO, HfGdO, YbSiO, CeZrO, and CeGdO were examined. Inaddition, AO-type materials, like Al₂O₃, Y₂O₃, Yb₂O₃ and HfO₂ and ZrO₂,were also examined as comparative references. It was found that the ABOor ABCO materials, or complex binary or ternary oxides, provided morestable compounds compared to the AO family of simple oxides.

In order to determine which compositions would be the best to use foreventual plasma spay applications, the initial evaluation of materialsinvolved the use of sintered ceramic samples using conventionalsintering methods in consideration of the low cost and ease ofmanufacturing. Sintered ceramic reference or comparative (AO-type oxidematerial) samples were made, including Y₂O₃, Yb₂O₃ and HfO₂. Inaddition, sintered ABO-type material test samples were also made,including Y_(0.15)Zr_(0.85)O_(1.93), Y₂Si₂O₇, Yb₂Si₂O₇,Ce_(0.25)Zr_(0.75)O₂, Ce_(0.7)Gd_(0.3)O₂ and La₂Zr₂O₇.

Commercially available, high purity feedstock powders for each samplecomposition were mechanically mixed with 3-5 wt % of a polymeric binder,then pressed in the form of a 1 inch diameter samples that were 0.30inch thick. Each of the pressed samples was fired at 600° C. to burn offthe polymeric binder. These samples were then sintered from 1400-1600°C. for 10 to 15 to achieve 95-98% of the theoretical density of eachcomposition, and then cooled in the furnace over a period of 24 hrs. Thespecific sample compositions were sintered under the followingconditions:

Y₂O₃ at 1400° C. for 12 hours;

Yb₂O₃ at 1400° C. for 10 hours;

HfO₂ at 1400° C. for 10 hours;

Y_(0.15)Zr_(0.85)O_(1.93) at 1500° C. for 14 hours;

Y₂Si₂O₇ at 1400° C. for 10 hours;

Yb₂Si₂O₇ at 1400° C. for 12 hours;

Ce_(0.25)Zr_(0.75)O₂ at 1600° C. for 14 hours;

Ce_(0.7)Gd_(0.3)O₂ at 1600° C. for 14 hours; and

La₂Zr₂O₇ at 1600° C. for 15 hours.

The sintered samples were then ground and polished on both sides toachieve a thickness of 0.24 inch and the surface roughness was at least2 μin Ra. The samples were cleaned for 10 minutes in an ultrasonic bathfilled with deionized (DI) water and then dried in an oven at 85° C. for2 hrs. All samples were then cooled to room temperature prior to anysubsequent testing.

All of the test and comparative samples were then evaluated for acidsolubility in HCL and H₂SO₄, which are acids that are commonly used forcleaning semiconductor chamber components. The test and comparativesamples were fully immersed in 5 wt % HCl and also in 5 wt % H₂SO₄ atroom temperature (at 21° C.) for 24 hours, after which time the materialloss (in wt %) was measured. FIG. 1 shows the results of the comparativeand test materials with respect to the acid solubility. As shown in FIG.1, this data translates into poor wet cleaning resistance for Y₂O₃, thesolubility of which in HCl was 6 wt %, and the other AO-type oxides. Onthe other hand, the ABO-type complex oxides did not show any measurableacid solubility, which translates into good wet cleaning resistance.

Further experiments were done to determine the plasma etch resistance ofthe test and comparative sample materials. Table 1 shows fluorinechemistries that are widely used for dielectric and conductor etching.CF₄ and oxygen plasma were then selected as the etchants for thiscomparative evaluation of the plasma erosion rate of the selectmaterials. Table 2 shows the experimental conditions that were usedaccording to the present experiment.

TABLE 1 Commonly used Plasma Etch conditions in semiconductor tools.Bottom Bias Top RF Power, Power, Watts @ Process Process Gases Watts @13.56 MHz 13.56 MHZ Pressure, mtorr Dielectric Etch CF4/CHF3/SF6/O2 100to 1200 200 to 1000  30 to 300 Via Etch C4F6/CHF3/O2 400 to 1000 100 to1700 30 to 80 Conductor Etch Cl2/BCL3/O2 500 to 1000 100 to 200  10 to20

TABLE 2 Experimental Plasma Etch Conditions for the Present ExperimentsTop RF Power Bottom Bias Power Process Gasses Watts @13.56 MHZ Watts@13.56 MHZ Pressure, mtorr CF₄/O₂ 2500 250 40

As described in Table 2, the etch chamber was set to operate at 2500watts of top RF coil power and a bottom capacitive bias of 250 Watts. RFgenerators were set to operate at a frequency of 13.56 MHz and thechamber was maintained at a vacuum pressure of 40 mtorr. A flow rate ofthe ratio of 10 to 1 sccm was maintained for CF₄ to O₂ to strike theplasma. Each test sample was etched for 30 min. These harsh conditionswere selected to in order to accelerate the plasma erosion of the testand comparative sample materials for rapid testing purposes.

After the plasma exposure, the erosion rates of the test and comparativesample materials were measured by recording the thickness loss from theexposed surfaces of the samples. FIG. 2 shows relative plasma erosionrate results of the test and comparative materials, where the plasmaerosion of Y₂O₃ of 1 μm/Rf hour is used as a reference.

The plasma erosion data shows that the ABO or complex oxide materialshave lower plasma erosion rates compared to that of the AO or singleoxide-type materials.

EXAMPLES

Further wet corrosion studies and plasma erosion studies identified thatABO-type complex oxide materials provide a better solution forsemiconductor processing members with respect to reducing particlegeneration and improving the number of wet cleaning cycles compared toAO-type single oxides materials that have been used thus far. While thepreferred materials according to the present invention can be used assintered ceramics, where chamber components are made by sinteringceramics, it should be noted that such sintered ceramic components aremore expensive and brittle, and that such sintered ceramic parts canbreak if impacted. In contrast, thermal sprayed coatings made of thecomplex oxides according to the present invention offer a more robustand economical solution to reduce particles and improve wet cleaningresistance.

The examples below involve thermal spray technology to form protectivecoatings on substrates (semiconductor chamber component bodies)utilizing the preferred materials according to the present invention.

Comparative Example 1

A mechanically blended powder was made using La₂O₃ and ZrO₂ in blendratios to target a pyrochlore phase at 56 wt % La₂O₃ with a balance ofZrO₂ in a range of 50-60 wt % La₂O₃. Coatings were sprayed with a DCplasma arc spray system using Argon and Hydrogen plasma gasses. Theformed coatings showed a La₂Zr₂O₇ phase and the presence of free La₂O₃and ZrO₂. These coatings were tested for plasma erosion, but did notperform as well as compared to the Y₂O₃ coatings. These results wereundesirable.

Example 1

In view of the undesirable results in Comparative Example 1, powderswere then prepared where a solid solution of La₂O₃ and ZrO₂ was madewith La₂Zr₂O₇ phase, as verified by X-ray diffraction. Powder sampleswere prepared using conventional methods of crushing, sieving and spraydry agglomeration to provide an average particle size of 30 μm. Thepurity of the powder was maintained using powder manufacturing systemslined with plasma sprayed zirconia coatings or polymerics such that alltrace elements were less than 50 ppm, all heavy metals were less than 20ppm, and alkaline metals were less than 10 ppm, as measured by GlowDischarge Mass Spectroscopy (GDMS).

Coatings were made from this La₂Zr₂O₇ powder using a DC plasma arcsystem using argon and hydrogen with an envelope of argon around theplasma plume to form La₂Zr₂O₇ coatings. These La₂Zr₂O₇ coatings did notshow any weight loss when immersed in HCl for 24 hours. These La₂Zr₂O₇coatings were then subjected to an ultrasonic bath of deionized (DI)water at 40 KHz for 15 min, dried in an oven at 85° C. for at least 4hours, and then tested in the plasma etch chamber and exposed to thefluorine plasma conditions as shown in Table 2. The finish on theseLa₂Zr₂O₇ coatings did not change, and the measured plasma erosion ratewas 66% less than that that of the reference Y₂O₃ coating.

In view of the success of these test samples, a large part was made torepresent a shape commonly used in a plasma etch chamber. The part (1)was a cylindrical shell made from 6061 Al alloy and having an innerdiameter (ID) of 14 inch and 5 inch height (H), as shown in FIG. 3. Thethickness (T) of the cylindrical shell wall was 0.125 inch. The part (1)was grit blasted on the inner diameter surface and then the entire partwas hard anodized. The anodization film (2) thickness was about 0.002inch. A La₂Zr₂O₇ coating (3) having a coating thickness of 0.006 inchand made from the high purity, solid solution-formed La₂Zr₂O₇ powderdescribed above was then deposited on the inner diameter surface withoutany further grit blasting. The part was then cleaned in an ultrasonicbath filled with deionized (DI) water for 15 min and then dried in anoven at 85° C. for at least 4 hours. The coated part was placed in aplasma etch chamber to simulate a fluorine dielectric etch environment,and then a chlorine conductor etch environment according to theconditions shown in Table 1. The part was exposed to each of the plasmaetch conditions for 15 min for 5 cycles.

When the part was removed from the etch chamber, no erosion was observedon the coated surface. The inner surface of the removed part was wipedwith 5 wt % HF and then 5 wt % HCl. The part was then submerged in a DIwater ultrasonic cleaner for 10 min and the dried in an oven at 85° C.for at least 4 hours. This cycle of cleaning was repeated 10 times, andno coating delamination from the substrate occurred.

Example 2

The coating from the coated shell used in Example 1 was stripped offusing a grit blast method while preserving the anodization. Then theLa₂Zr₂O₇ coating according to Example 1 was reapplied to restoredimensions of the part. The part was again tested in the plasma etchchamber under the same conditions for 5 times with a cleaning cycle inbetween the process. The part showed no erosion or delamination of thecoating from the substrate.

During the plasma etching processes, Si wafers were also processed, andthe contamination levels on the wafers were measured by MassSpectroscopy using inductively coupled Plasma (MS-ICP). It was foundthat trace elements on the wafers were less than 10×10¹⁰ atoms/cm². Moreimportantly, heavy metal elements were less than 5×10¹⁰ atoms/cm², andalkaline metals were less than 2×10¹⁰ atoms/cm².

After the above-described testing, the coated part was sectioned and thecoating microstructure was revealed, as schematically shown in FIG. 4.The substrate (body) (1) made of 6061T6 Aluminum has an anodized film(2) on the outer surface thereof. The inner side of the substrate (body)surface was roughened and then anodized; this rough anodized interface(2R) was used to deposit the La₂Zr₂O₇ coating (3) without grit blasting.The coating (3) showed no signs of voids within its microstructure, andthere was no delamination of the coating from the substrate at interfacebetween the rough anodized interface (2R) and the coating (3),indicating that the coating did not corrode in the chamber or during thewet cleaning process.

The hardness of the coating in cross-section was measured to be in arange of 500 to 600 kg/mm², and the porosity was measured to be lessthan 1%.

Example 3

A part having the shape of a cylindrical shell (14 inch ID and 5 inchheight) made of 6061 Al alloy was coated in the same manner as describedabove in connection with Example 1. This time, the surface of theLa₂Zr₂O₇ coating was textured using a series of flexible pads withbacking for diamond coated abrasives. Specifically, 60 μm and then 30 μmdiamonds were used as abrasives to texture the coated surface to removeonly high spots from the coated surface. This flexible finishing methodprovided the coated surface with a roughness Ra in a range of 80 to 120pin. The removal of high spots also provided a peak to valley ratio,Rp/Rv of the surface roughness in a range 0.3 to 0.6.

The part was then cleaned in an ultrasonic bath filled with DI water at40 KHz at 60° C. for 15 min. Measurement of the particles entrained inthe cleaning fluids by a laser particle counter showed a drop of 50% inthe total particle count compared to that of Example 1. The part wasthen dried in an oven at 85° C. for at least 4 hours. The coated partwas then placed in a plasma etch chamber to simulate a fluorine plasmaetch environment for 30 min. This time, the 200 mm wafers that were alsosimultaneously processed were examined to determine the number ofparticles landing thereon. Only one particle was detected in a run where10 wafers were processed.

Example 4

To further confirm the validity of using complex oxides for plasmaerosion application in semiconductor tools, a powder of the compositionCe_(0.25)Zr_(0.75)O₂ as a solid solution was made using high puritymaterials, where the content of heavy metals was less than 20 ppm, thecontent of alkaline metals was less than 5 ppm, and the content of Fe,Cu or Ni was less than 5 ppm each. The powders of the composition had anaverage particle size of 20 μm. The powder was sprayed with a DC plasmaspray system, using argon and hydrogen, with an envelope of argon aroundthe plasma plume to minimize entrainment of air into the effluent. Freestanding Ce_(0.25)Zr_(0.75)O₂ coatings were made and then differentsamples were immersed in one of HCL and H₂SO₄ for 24 hours. TheseCe_(0.25)Zr_(0.75)O₂ coatings did not show any significant weight lossin either acid exposure test. Samples of Ce_(0.25)Zr_(0.75)O₂ coatingsexposed to fluorine plasma for 30 min showed 60% less erosion ascompared to the reference Y₂O₃ coating.

Example 5

Powder was also made of Ce_(0.7)Gd_(0.3)O₂ as a solid solution(hereinafter GDO powder), where the average particle size was 30 μm. TheGDO powder was a high purity content to maintain all trace elements toless than 50 ppm, as verified by GDMS. Free standing coatings were madewith the CGO powder, and when the coatings were immersed in HCL andH₂SO₄ for 24 hours, no weight loss was measured. Samples of the GDOcoatings exposed to fluorine plasma for 30 min showed 58% less plasmaerosion compared to the reference Y₂O₃ coating.

Example 6

A first set of 3 cylindrical test samples having a diameter of 1 inchand a length of 1.5 inch were made of 6061 Al alloy. Bare Al alloycoupons were grit blasted on the 1 inch diameter face, and a La₂Zr₂O₇solid solution coating of 0.012 inch thickness was deposited on the gritblasted surface by the plasma spray coating process described inconnection with Example 1. The tensile bond strength of the coating wasmeasured according to the ASTM C633 standard method, and was determinedto be an average of 8,900 psi.

Another set of 3 cylindrical samples were grit blasted and then anodized(hereinafter referred to as anodized Al alloy coupons). A La₂Zr₂O₇ solidsolution coating of 0.012 inch thickness was deposited on the 1 inchdiameter face. The tensile bond strength of the coating was measured tobe an average of 7,900 psi.

The bare Al alloy and anodized Al alloy samples having the coatingsthereon were cycled to 300° C. 10 times. It was found that the tensilebond strength of the coating on the anodized Al alloy surfaces wasreduced by 5%, whereas for bare Al alloy surfaces, the tensile bondstrength of the coating was reduced by 30% under the same conditions.

Another set of bare and anodized Al alloy test samples were first coatedwith an Si bond coating layer, and then with the La₂Zr₂O₇ coating. Thetest samples were then cycled 10 times from room temperature to 300° C.,and then the tensile bond strength of the test samples was measured.These samples did not show any significant decrease in tensile bondstrength of the coating.

Another set of samples were prepared, both with and without bond layers,as described in more detail below. A cross-section of a sample includinga bonding layer 4 is shown schematically in FIG. 5. This sample (1) wasfirst roughened on one side and then anodized on all surfaces. Theanodization on the non-roughened surface is shown as (2) and theroughened interface is shown as (2R). Then a bond layer (4) wasdeposited. This time, the bond layer coating (4) was made of a co-phaseof fully stabilized zirconia (FSZ) and Y₂O₃ coating, where Y₂O₃ was 18wt. %. Then a top layer coating (3) of La₂Zr₂O₇ was deposited on thebond layer (4). Both of these samples were cleaned with HCl and thenimmersed in DI water in an ultrasonic tank for 5 minutes. These sampleswere then tested for tensile bond strength. It was found that the testsamples with bond layer showed no decrease in bond strength, whereas thetest samples without a bond layer showed a 25% decrease in bondstrength.

Example 7

It is critical to maintain the purity of the coatings in semiconductorchambers in order to maintain the functionality of the transistordevices that are formed in such processing chambers. To understand thepurity of the formed coatings, a set of 4×4×0.125 inch coupons werecoated with a La₂Zr₂O₇ solid solution coating. The surfaces wereexamined by GDMS after laser ablation of the surface in successivesteps, where the coating was removed by rastering a laser beam on thecoated surface and the coated surface was ablated in steps to a depth of0.001 inches and then the trace elements of each exposed coating surfacelayer were measured by GDMS. This measurement method showed that throughthe thickness of these coatings, that there were no trace metal elementsin excess of 20 ppm (i.e., less than 10 ppm, and for critical elementsof Na, K, Mg, Fe, Cr and Ni, and less than 5 ppm or even less than 2 ppmfor Fe, Ni and Cu).

Example 8

A solid solution powder was made with a La_(1.5)Ce_(0.5)Zr₂O₇ phase,where the average particle size of the powder was 20 μm. Coatings weremade using the plasma spraying methods according to Example 1. A set ofsamples, hereinafter referred to as bend strips, being 6 inch in length,1 inch in width and 0.125 inch in thickness, made of 6061T6 Aluminumalloy, were coated with La_(1.5)Ce_(0.5)Zr₂O₇ coatings of 0.004 inchthick. Reference samples were also made having the same dimensions andcoated with La₂Zr₂O₇ solid solution coatings of the same thickness.These bend strips were bent in a fixture around a mandrel of 0.5 inchdiameter. It was found that the La₂Zr₂O₇ coatings started cracking andspalling from the substrate earlier than the La_(1.5)Ce_(0.5)Zr₂O₇coatings during this bend test, which indicated an increase in ductilityand adhesion strength of the La_(1.5)Ce_(0.5)Zr₂O₇ coating due to theternary phase formation in the presence of CeO₂ as verified by x-raydiffraction.

Example 9

An electrostatic chuck (ESC) coated with Y₂O₃ that showed surfaceerosion and higher helium leak rates when used in a chlorine plasma etchenvironments was obtained. The chuck surface was provided with aLa₂Zr₂O₇ solid solution coating on the surfaces that are exposed toplasma conditions for dielectric etching. The chuck was used again inthe plasma chamber under the same conditions, and showed no erosion ofthe surfaces that were protected with the La₂Zr₂O₇ coating, and theelectrostatic chuck continued to provide electrostatic clamping to aworking substrate with very stable helium leak rates. FIG. 6 shows thatthere was no increase in backside gas leak rates due to higher erosionresistance of the sealing surfaces of the ESC coated with La₂Zr₂O₇ ascompared to the one coated with Y₂O₃. Use of the high purity, solidsolution La₂Zr₂O₇ coatings also resulted in very little transfer oftrace elements to the wafer. Trace elements of heavy metals like Cr, Fe,Ni and Cu were less than 1×10¹² atoms/cm², and Na was less than 1×10¹⁴atoms/cm², as measured by Mass Spectroscopy using Inductively CoupledPlasma instrumentation (MS-ICP).

Example 10

A sintered ceramic part made from Al₂O₃ that showed an excessiveformation of AlF₃ particles in a plasma chamber was coated with 0.004inches of a Ce_(0.7)Gd_(0.3)O₂ solid solution coating. The coated part,when installed in a semiconductor etch tool in the plasma zone did notshow any formation of AlF₃ particles when exposed to fluorine plasma. Apolymer film, which is a byproduct of the fluorine etching process,begins to build up as soon as Rf exposure begins and was deposited onthe part. After about 100 Rf hours, the buildup is measurable andrequires removal. The part was removed from the chamber, theCe_(0.7)Gd_(0.3)O₂ coating was removed by grit blasting, and then a newcoating layer was applied to restore the part to full functionality.

The various examples above illustrate the use of complex oxide coatingsto prevent plasma erosion of various components used in semiconductorprocessing members.

While the present invention has been particularly shown and describedwith reference to the preferred mode as illustrated in the drawings, itwill be understood by one skilled in the art that various changes indetail may be effected therein without departing from the spirit andscope of the invention as defined by the claims.

What is claimed is:
 1. A semiconductor processing member comprising: a body; and a plasma spray coating provided on said body; wherein said plasma spray coating is an ABO or ABCO complex oxide solid solution composition selected from the group consisting of La₂Zr₂O₇, La_(1.5)Ce_(0.5)Zr₂O₇, Ce_(0.25)Zr_(0.75)O₂, Ce_(0.7)Gd_(0.3)O₂, and Y_(0.15)Zr_(0.85)O_(1.93); whereby said plasma spray coating imparts both chlorine and fluorine plasma erosion resistance, reduces particle generation during plasma etching, and prevents spalling of said plasma spray coating during wet cleaning of said member.
 2. The semiconductor processing member according to claim 1, wherein said plasma spray coating contains less than 50 ppm of any trace element.
 3. The semiconductor processing member according to claim 2, wherein the plasma spray coating contains less than 20 ppm of any heavy metal, less than 10 ppm of any alkaline metal, and less than 2 ppm of each of Fe, Ni and Cu.
 4. The semiconductor processing member according to claim 1, wherein the body is a bare aluminum alloy body.
 5. The semiconductor processing tool according to claim 1, wherein the body is an anodized aluminum alloy body.
 6. The semiconductor processing member according to claim 1, wherein an outermost surface of said plasma spray coating has a surface roughness in a range of 80 to 150 μin Ra, wherein a peak to valley ratio, Rp/Rv, of said surface is in a range of 0.30 to 0.60.
 7. The semiconductor processing member according to claim 1, further comprising a bonding layer between the plasma spray coating and the body to improve a tensile bond strength of said coating.
 8. The semiconductor processing member according to claim 7, wherein said bonding layer is selected from the group consisting of (1) Si and (2) co-phased fully stabilized zirconia and Y₂O₃.
 9. The semiconductor processing member according to claim 1, wherein said plasma spray coating reduces contamination of a working wafer in the semiconductor tool so that an amount of Na measured on the wafer is less than 1×10¹⁴ atoms/cm².
 10. A semiconductor processing member comprising: a body comprising one of a bare aluminum alloy body and an anodized aluminum alloy body; a plasma spray coating provided on the body; and a bonding layer between the plasma spray coating and the body to improve a tensile bond strength of the plasma spray coating, wherein the bonding layer is selected from the group consisting of (1) Si and (2) co-phased fully stabilized zirconia and Y₂O₃; wherein the plasma spray coating is an ABO or ABCO complex oxide solid solution composition, where A, B and C are selected from the group consisting of La, Zr, Ce, Gd, Y, Yb and Si, and O is an oxide; and whereby the plasma spray coating imparts both chlorine and fluorine plasma erosion resistance, reduces particle generation during plasma etching, and prevents spalling of the plasma spray coating during wet cleaning of the member.
 11. The semiconductor processing member according to claim 10, wherein the plasma spray coating is selected from the group consisting of La₂Zr₂O₇, La_(1.5)Ce_(0.5)Zr₂O₇, Ce_(0.25)Zr_(0.75)O₂, Ce_(0.7)Gd_(0.3)O₂, Y_(0.15)Zr_(0.85)O_(1.93) and Y₂Si₂O₇.
 12. The semiconductor processing member according to claim 10, wherein the plasma spray coating contains less than 50 ppm of any trace element.
 13. The semiconductor processing member according to claim 12, wherein the plasma spray coating contains less than 20 ppm of any heavy metal, less than 10 ppm of any alkaline metal, and less than 2 ppm of each of Fe, Ni and Cu.
 14. The semiconductor processing member according to claim 10, wherein an outermost surface of the plasma spray coating has a surface roughness in a range of 80 to 150 μin Ra, wherein a peak to valley ratio, Rp/Rv, of the surface is in a range of 0.30 to 0.60.
 15. The semiconductor processing member according to claim 10, wherein the plasma spray coating reduces contamination of a working wafer in the semiconductor tool so that an amount of Na measured on the wafer is less than 1×10¹⁴ atoms/cm². 